1. Field of the Invention
The present invention relates to the testing for the presence of toxic substances and more particularly to a new, inexpensive, portable, hand held means for testing in a field environment for the presence of toxic substances involving the use of the microscopic, bioluminescent marine organisms.
2. Description of the Prior Art
Bioluminescence has been the subject of considerable research, and its measurement for the most part has been by a relatively complex photomultiplier photometer designed by McNicholls in 1952, Methods Biochem Anal. 861; modified subsequently by Mitchell, Hastings and Strickland, "A practical Handbook of Seawater Analysis," 2nd ed. Bull. 167, Fisheries Research Board of Canada; and most recently by Stiffey et al. There are many commercially available photometers, but all are expensive; are not adaptable for field operations; and can detect only intermittent light emissions.
For example, the tester described in U.S. Pat. No. 4,950,594 issued to Stiffey et al, Aug. 21, 1990 requires the samples of suspected toxic substances to be transported over long distances to a laboratory environment, for example, oil well drilling fluids used in offshore oil well drilling operations. Also this procedure had to be carried out in a darkened room to prevent extraneous light from reaching the photomultiplier tube and to reduce desensitization of the organisms by exposure to light. Many toxins tend to degrade while being transported from the field to the laboratory, thus leading to detoxification and consequently misleading test results.